Manufacture of stencil sheets



Patented Aug. 1 1921.

UNITED STATES PATENT OFFICE.

ALEX BROCKING DAVIS, OI CINCINNATI, OHIO, ASSIGNOR TO A. DICK COMPANY OFCHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

muracrunn or STENCIL snnn'rs.

Io Drawing. Original application filed February 5, 1926, Serial No.88,848. Divided and this application filed August 5, 1828. a

Reference is hereby made to an application filed by me February 5, 1926,for stencil sheets and coating masses therefor, Serial No. 86,343, ofwhich this application is a division.

The present invention relates particularly to stencil. sheets made bydepositing upon a porous base sheet, such as Japanese oshino paper, ahomogeneous type and sty us im- 10 pressible film. Many tvpes ofstencils of this character have a ready been made, either by drawin theJapanese yoshino paper through mo ten coating masses such as those whichmay be compounded from waxes, gums, etc., or by deposlting upon theyoshino sheet homogeneous films by drawing the sheets throu h solutionsof various substances and allowmg the volatile solvent to evaporate.Other processes than the two above stated have been used for depositinthe film upon the yoshino paper, but al forms ofstencil sheets so farproduced have possessed certain disadvantages, such as lack of strengthand working qualities deterioration on standing, or the easy breaking ofthe film unless the paper be handled with care.

The object of this invention is to provide,

a new stencil coatin mass which-eliminates many or the usualdifficulties of production,

and to provide stencil sheets possessing marked advantages as totoughness, cleannessof impression, working qualities, and

which kee without deterioration when stored for ong periods. Otherobjects of my invention will be in part obvious and in part pointed outhereinafter.

In carrying out the invention, I may proneed as icilowsz;

Acetone-soluble cellulose acetate such as ficial silk is dissolved inacetone to a. 10% solution b" weight. According to the character oi thecotton used in the production of the cellulose acetate and'the method ofacetylation, the viscosity of the cellulose acetats solution varies overwide limits, and while all types of the cellulose acetate which if havebeen able to obtain will give a stencil sheet, I prefer to use thatgrade whichmay be called medium viscosity. Into. a. suitable vesselthere is placed 120 parts by is normally used for the production ofarti-- Serial No. 127,488.

weight of this 10% cellulose acetate solution in acetone. There is nowadded 200 parts by weight of acetone. Into this mass there is nowstirred 100 parts by weight of mono benzoyl butyl tartrate, in which hasbeen dissolved 20 parts by weight of chlorinated naphthalene, and forthis material I prefer.

the solid chlor derivatives consistin mainly of the tetra, penta andhexa ch or compounds. The mono benzoyl butyl tartrate, which I believeto be a hitherto unused and unknown substance, is made preferably byreacting upon the dinormal butyl ester of tartaric acid withbenzoylchloride by heating the two substances together'untilhydrochloric acid ceases to be given off and the resultin oil reactspractically neutral.

Into the resulting mass there is now stirred as a pigment to lend oacity 10 parts by weight of zinc oxide which has been previously groundin 10 parts by weight of butyl tartrate. The mass is now stirredthoroughl' and forms a homogeneous lacquer-like ody, from which stencilsmay be produced by drawing sheets of Japanese 1yloshino paper, or othersuitable porous, brous base sheets, through .or over and removing theexcess by pulling the sheets over a wire. The resulting stencil sheetsare then hung up on. racks to allow the volatile solvent, principallyacetone, to evapw orate. This evaporation takes place very rapidly, andin a comparatively short period of time the sheets may be removed to bemounted upon proper backing sheets, ready for use in the typewriter orwith the st lus for the production of stencils to be use on duplicatingmachines. Such sheets are semi-opaque nearly white in color, and possessa marked degree of toughness. The film does not break easily or crack,and the stencils which result from the use of the typewriter or stylusgive very superior re sults in number of copies, and the excellence ofthe work which they produce is easily evident upon examining the copies,particw larly when a high grade ink best suited for the work is used onthe duplicating machine.

An alternative formula which 'ves results of a highly satisfactory ansimilar character is as follows, all parts being by weight:

It is obvious from the above formula that certain constituents may beregarded as basic and essential, particularly the cellulose acetate, andcolor must be lent by a pigment or a dyestufi, but the remainingingredients ma be replaced or substituted by other materlals of slightlydifferent composition. For instance, the mono benzoyl butyl tartrate maybe replaced by other derivatives of butyl tartrate in which one or moreof the hydroxyls of the tartaric acid radical have been combined withsome other acid; thus, I have found mono acetyl butyl tartratesatisfactory. The chlorinated naphthalene may be replaced by otherhydrocarbons or halogenated hydrocarbons, particularly those of theanthracene series, such as anthracene itself and carbazol. The diamylphthalate in the second formula may be exchanged for butyl phthalate andthe castor oil for other vegetable or animal oils of similar characterand properties.

As a further aternative formula, the following will serve To 75 grams of10% solution of cellulose acetate in acetone, there is added 25 grams of33% solution of starch acetate in acetone. There is now stirred in 70grams of mono benzoyl butyl tartrate and 15 grams of a halogenatedaromatic hydrocarbon, such as hexachlor naphthalene. A quantity ofcoloring matter or pient may be added to give color to the mass.

- In the above formula, the application of the invention is broadenedby. the use as a constituent of a second carbohydrate ester in the formof starch acetate, showing the broad application of the invention tocarbohydrate esters in general and particularly for the production ofcoating masses for the manufacture of stencil sheets.

The mono benzoyl butyl tartrate used primarily in the description ofthis invention is only a re resentative of a group of substances whicmay be classed as acid substituted derivatives of hydroxy'acid esters, a

large number of which I have found to possess properties similar to themono benzoyl butyl tartrate and upon which I have a group patent pendingat the present time.

\ Acetylamyl tartrate, benzoyl amyl salicV- late, benzoyl eth l lactate,and kindred-sub stances, all of w ich may be classed as acid substitutedbydroxy acid esters, fall within the scope of this invention asrepresentative of substances which may be used inpla'ce of the monob'enzoyl butyl tartrate, and I therefore, do not restrict myself to anyparticular representative of this group of substances as a primarymodifying agent in formulae of the character given above.

Stencils produced from this coating mass are capable of yielding largenumbers of copies when used with the usual forms of duplicatingmachines, andthe im ressions which they give are clean of line ansharply defined; in fact, the number of impressions which can. beobtained from these stencils, even on power driven duplicating machines,is far greater than the requirements of the average user for anyindividual stencil.

Now having described my invention, what I claim is 1. A type-impressiblestencil sheet coating including cellulose acetate and benzoyl butyltartrate.

2. A type-impressible stencil sheet coating including cellulose acetateand mono benzoyl butyl tartrate.

3. A type-impressible stencil sheet coating including cellulose acetateand an ester of tartaric acid in which at least one hydroxyl has beencombined with an acid radical.

a. A type-impressible stencil sheet coating including cellulose acetateand an acid substituted diallryl ester of tartaric acid.

5. A. type-impressible stencil sheet coating including cellulose acetateand an acid substituted dialkyl ester of tartaric acid and a halogenatedhydrocarbon.

6. A type-impressible stencil sheet coating including cellulose acetate,an acid substi-' tuted dialkyl ester of tartaric acid and a hydrocarbon.s

'2'. -A type-impressible stencil sheet coating includingcelluloseacetate, a tartaric acid ester, an acid substituted dialkylester of tartaric acid and an ester of phthalic acidf 8. Atype-impressible stencil'sheet coating including cellulose acetate, atartaric acid ester, an acid substituted dialkyl ester of tartaric acid,an ester of phthalic acid and a halogenated hydrocarbon. 9. Atype-impressible stencil sheet coating including cellulose acetate, atartaric acid ester, an acid substituted dialkyl ester of tartaric acid,an ester of phthalic acid and a hydrocarbon.

10. A t pe-impressible stencil sheet coating inclu ing celluloseacetate, an acid substituted tartaric ester and a vegetable oil.

11. The process of manufacturing a typeimpressible stencil sheet for usewith duplicatmg machines, which consists of depositing upon a porousbase sheet a homo eneous film including cellulose acetate and enzoylbutyl tartrate by means of a volatile solvent.

12. The process of manufacturing a typefilm including cellulose acetatean impressible stencil sheet for use with duplieating machines, whichconsists of depositing upon a porous base sheet a homo eneous monobenzoyl butyl tartrate.

13. The process of manufacturing a typeimpressible stencil sheet for usewith duplicatmg machines, which consists of depositing upon a porousbase sheet a homogeneous film including cellulose acetate and an esterof tartaric acid in which at least one hydi'loxyl has been combined withan acid radic 14. The process of manufacturing a typeimpressible stencilsheet for use with duplieating machines, which consists of depositingupon a porous'bas'e sheet a homogeneous cellulose acetate and an acidsubstituted dlalkyl ester of tartaric acid.

15. The process of manufacturing a typeimpressible stencil sheet for usewith duplieating machines, which consists of depositing upon a porousbase sheet a homogeneous film including cellulose acetate, an acidsubstituted dialkyl ester of tartaric acid and a halogenatedhydrocarbon.

16. The process of manufacturing a typeimpressible stencil sheet for.use with duplieating machines, which consists of depositing upon aporous base sheet a homogeneous film including cellulose acetate,an'acid substituted dialkyl'ester of tartaric acid and a hydrocarbo I17. The process of manufacturing, a type.-

' impressible stencil sheet for use with dupli eating machines, whichconsists of depositing upon a porous base sheet a homogeneous filmincluding cellulose acetate, a tartaric acid ester, an acid substituteddialkyl ester otdtartaric acid and an. ester of phthalic aci 18. Theprocess of manufacturing a typeimpressible stencil sheet 'for usewithduplicating machines, which consists of de ositing upon a porous basesheet a omo- .geneous film including cellulose acetate, a tartaric acid.ester, an acid substituted d1- alkyl ester of tartaric acid, .an esterof phthalic acid and a halogenated hydrocarbon.

19. The process of manufacturing a typeimpressible stencil sheet for usewith duplicatmg machines, which consists of depositing upon a porousbase sheet a homogeneous film including cellulose acetate, a tartaricacid ester, an acid substituted dialkyl ester of tartaric acid, an esterof phthalic acid and a-h drocarbon.

20. T e process of manufacturing a typeimpressible stencil sheet for usewith duplicatmg machines, which consists of depositing upon a porousbase sheet a homogeneous film including cellulose acetate, an acidsubstituted tartaric ester and a ve etable oil.

21. A t pe-impressible stenci sheet coating inclu ing an acidsubstituted hydroxy acid ester and a carboh drate ester.

- 22. A t pe-impressib e stencil sheet coating inclu mg a carbohydrateester and a' hydroxy acid ester at least one hydroxyl of which has beencombined 7 with an acid group.

23. A type impressible stencil sheet in- ALEX BROOKIN G DAVIS.

